Apart from the cost of maintenance to keep these "bird slicers" (a minor amount of carnage, of course, but I love the term) running, what they fail to tell you is that this variable power source requires a conventional power source as a backup: a fossil fuel burning one.
Now what they also give the impression is that when the wind stops blowing just as EastEnders starts, they press a button and the standby power station does the business.
Let me tell you, having worked on a power station and refinery in a former life, one does not simply press a big start button and voila: instant power. It can take several days to "black start" a power station.
In order to get the power to the grid quickly, the power station must be in "standby" mode i.e. its furnaces lit, the steam generated and pressured and possibly the turbines rotating.
So while these windmills are busy spinning away keeping the thicky green eco-nazis happy in blissful ignorance and couscous salads, a nasty old backup power station is quietly burning fossil fuels in the background.
Tax, tax and more tax and subsidies to large corporations.
These idiots simply wont be happy until horses are towing our Volvos.